Here's the round 1 doors before they open. You can see there are 3 doors for the attackers to come through.
...and after they open. The lower door has like the coolest opening animaiton ever. It seriously looks like a big deal when they do.
Round 3 starts with an elevator ride up a shaft for the attackers. The defenders can get as far as the top of the shaft, but that's sealed off untill the round starts. (There will be 2 nearby but very small exits that will each be a lot like the side exit in dustbowl round 1). This is the elevator. Yes the wheels roll up and down. With any luck it'll be possible to build SGs on movable objects in FF and we might witness the advent of the offensive sentry gun
And the top of the shaft.
Please note that these screens are fairly wip-y, especially the last one where most of the cliffs are missing.
But there we go. I'm still trying to work up the courage to map the round 2 section.